1. Field of the Invention
This invention relates to a complementary-conducting-strip (CCS) structure (or waveguide cell) to construct a waveguide array structure for transmission line circuit design, the CCS structure is formed by integrated circuit process to accomplish a miniaturized microwave monolithic circuit.
2. Description of the Related Art
Integrating monolithic electronic circuits or miniaturizing a system on a chip is a tendency on integrated circuit design; however, miniaturizing a microwave communication system is not easy, because large amounts of distributed elements are employed in microwave circuits. Even though a lot of the elements are miniaturized, transmission lines in microwave usually take a large area of the circuits.
Monolithic microwave integrated circuits (MMICs) made by GaAs technology had often extensively used two distinct transmission lines (TLs) structures: 1) microstrip line (MSL) with backside metallization and via holes, and 2) coplanar waveguide (CPW) with air bridges. III-V compounds such as GaAs semiconductor technology have superior electrical performance to silicon-based processes, like CMOS and SiGe BiCMOS, due to their higher electron mobility, higher breakdown voltage, and the ability of making high quality factor (Q-factor) passive components. With continuing evolution in process and technology, silicon-based technologies, however, promise a higher level of integration and lower cost than the III-V counterparts, thus making a multifunction RF transceiver or an RF system-on-chip (SOC) a reality.
In the present, more and more electrical engineers miniaturize monolithic circuit in microwave through complementary metal oxide semiconductor (CMOS) technology. CMOS technology promises a higher level of integration and lower cost, enabling the production of multifunction wireless transceivers and communication system on single chip design. The transmission line frameworks in CMOS technology also satisfied broadside-coupler, co-planar waveguide (CPW) and meandering solutions. Moreover, microwave transmission elements would be accomplished in a three-dimensional monolithic microwave integrated circuit (3D MMIC) in order to save area of a chip. The concept of synthetic quasi transverse electromagnetic (quasi-TEM) transmission line successfully employed to miniaturize RF integrated circuits in the highest degree.
Extensive studies indicate that the synthetic quasi-TEM transmission line has better guiding properties than those of the conventional micro strip when the signal trace is meandered in a two-dimensional plane. Following the same concept of miniaturization, this work focuses on the design of the quasi-TEM transmission line using standard 0.18 μm 1P6M CMOS technology, which is available from most standard silicon foundry services in the world.